Like most of the people who love this studio, I go because it is easy on my body. I love Core Power and go there for my workout. Kindness is where I move slow and restore. There are really only a couple of teachers who challenge with heated power classes, and those are great just not offered much.
Kindness is known for dharma talks, mellow movement and nice feelings. That's why it gets my vote, just slightly over Core Power. And it is donation based, instead of $20 like CP, so I get to practice for $5-10 which works with my budget.